Q&A - PSLE Math

[tianzhu]

Hi Brenda10 and Hifive


Good Morning

You’re welcome.

Wishing you a fabulous and prosperous 2011.

Good cheers, good health and good PSLE results.

Best wishes

[tianzhu]

Belle2011:

In a primary school, 50 pupils were surveyed on the pets they liked. 80% of the pupils liked dogs, 50% of them liked birds and 34% of them liked rabbits. The survey results were that 1 out of every 5 pupils did not like any of the animals.
What is the least number of pupils who liked all 3 types of animals.
(model ans : 2).

Hi Belle2011

Good Morning

Number of pupils who did not like any of the animals -----1/5*50 ----- 10
Number of pupils who like any of the animals -------40 (50-10)

Number of pupils who like dogs ------ 40 (80%)

Number of pupils who like birds ------ 25 (50%)

Number of pupils who like rabbits ------ 17 (34%)

The tricky part starts from here; I think one needs to have some knowledge about Set notation and Venn diagram to be able to understand the steps better.Therefore, I am not sure if your question is within PSLE syllabus.

As calculated earlier, the number of pupils who like any of the animals is 40. However 40+25+17 adds up to 82.

Here a Venn diagram will come in handy.

25+17 --- 42
42-40 --- 2

If you draw a Venn diagram, you’ll see that the number of pupils who like dogs and birds is equal to 23 and the number of pupils who like dogs and rabbits is equal to 15 and the number of pupils who like all three types of animals is 2.This adds up to 40.

Wishing you a fabulous and prosperous 2011.

Good cheers, good health and good PSLE results.

Best wishes

PS --- You may follow these links to learn more about Venn diagram.

http://www.youtube.com/watch?v=nf-pnW_wVRw&feature=related

http://www.youtube.com/watch?v=mMh0QdPHTRM&feature=related

[Belle2011]

Dear tianzhu,

Thanks very much for your help.

Cheers,
Belle.

[tianzhu]

Belle2011:

Dear tianzhu,

Thanks very much for your help.

Cheers,
Belle.

Hi Belle2011

You're welcome.

Wishing you a very successful PSLE 2011.

Best wishes

[Brenda10]

tianzhu:

Hi Brenda10 and Hifive


Good Morning

You’re welcome.

Wishing you a fabulous and prosperous 2011.

Good cheers, good health and good PSLE results.

Best wishes

Hi Tianzhu

Thank you for your great help and good wishes.

We do wish you good health, good luck and a prosperous 2011 too.

Hopefully by learning more from you and other experts, the children are able to do well in the coming PSLE.

Cheers

[Vanilla Cake]

tianzhu:

Hi VC


I believe there are diagrams provided in Q17.
The first slide helps to explain the addition of rods to form the structures.
Hope this helps.
Best wishes.
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Dear Uncle Tianzhu,
This is the actual question in the PSLE 2010 Maths exam for your reference:
Together with this post, I wish you and your family - a very happy new year 2011. May your wishes + dreams be fulfilled and be blessed with good health, happiness and abundance.
Thank you.

http://postimage.org/image/298ne8un8/

[tianzhu]

Hi VC


Good Morning

Thank you for posting the original question. Time really flies. Yesterday I saw the latest edition of PSLE question book in Popular. I believe PC (Perseverance) must have bought one already.

May you leap into 2011 with happiness, abundance and good health. May your results improve by leaps and bounds.

I believe you’ve grown into a tall, beautiful and elegant lady now. I hope you’ll continue to enjoy your studies and achieve sterling performance.

And if I may add, don’t get distracted by handsome hunks now , spend more time with your parents and concentrate on your studies.

Please send my regards to chocolate cake and David Koriadi.

Best wishes

[tianzhu]

Hi Belle2011


Hope this helps.

To begin with, I am wondering if this question is within the PSLE syllabus.
I think I saw such question under direct/Inverse proportion in secondary two textbooks.

There are three variables in this question, namely the number of men, the number of houses and the number of days. The key to unlock this question is to keep one variable constant at any one time.

I have included more steps to enable better understanding; as usual,you may consolidate some of the steps once you are able to grasp the concepts better.

Best wishes

http://farm6.static.flickr.com/5121/5311612758_7e7f64389e_b.jpg\">

[Hifive]

Hello everyone


HAPPY NEW YEAR!

I’ve a question:

Peter, Queenie, Regina and Sally saved $1030. The ratio of Peter’s money to Queenie’s money was 1 : 2. Peter took 2/5 of Regina’s money. He then gave $95 from the amount taken from Regina to Sally. Finally, the 3 girls had the same amount of money.

a) How much did Regina have at first ?
b) How much did Sally have in the end?

Appreciate your advice.

[Dharma]

Hifive:

Hello everyone


HAPPY NEW YEAR!

I've a question:

Peter, Queenie, Regina and Sally saved $1030. The ratio of Peter's money to Queenie's money was 1 : 2. Peter took 2/5 of Regina's money. He then gave $95 from the amount taken from Regina to Sally. Finally, the 3 girls had the same amount of money.

a) How much did Regina have at first ?
b) How much did Sally have in the end?

Appreciate your advice.

At first, their share
Peter : 3u
Queenie : 6u
Regina : 6u + 4u = 10u
Sally : 6u - $95

25u - $95 = $1030
25u = $1125
1u = $45

a) Amt Regina had at first = 10u = $450
b) Amt Sally had in the end = 6u = $270